There has been proposed an electrophotographic image forming apparatus in which one or more consumable units such as imaging unit and/or toner cartridge are detachably mounted on the apparatus.
Typically, the consumable unit has a nonvolatile memory, for example, which memorizes various information such as identification thereof. When the consumable unit is mounted on the image forming apparatus, the identification memorized in the nonvolatile memory is retrieved into a control of the apparatus. The control has a memory such as nonvolatile memory where the identification or identification information is memorized.
When the consumable unit is replaced and then any recovery action is performed such as turning on the power switch, clearing the power saving mode, or closing the operational door of the apparatus, the control of the apparatus performs operations indicated in FIG. 22, for example.
As shown in FIG. 22, when the recovery action is started, the identification information of the newly mounted consumable unit is retrieved (step S201) and read (step S202). Using the read identification information, it is determined whether the dismounted consumable unit is remounted in the image forming apparatus (step S203). If it is determined that a new consumable unit is mounted, the information in the nonvolatile memory of the consumable unit is read (step S204), which is used for the subsequent image adjustment control (step S205). If, on the other hand, it is determined that the same consumable unit is remounted to the image forming apparatus in step S203, the step S204 is not performed and, based on the information of the consumable unit memorized in the nonvolatile memory of the image forming apparatus, the image adjustment control is performed (step S205). A process similar to that of step S203 is disclosed in JP 10-198236 A.
Typically, an inexpensive nonvolatile memory is used for the consumable unit for the economical reason. This causes a delay in communication so that a considerable time is required for retrieving and reading the identification information and for reading data other than the identification information. Also, the nonvolatile memories are connected to the same serial bus, which further delays the communication speed. As a result, the recovering action needs a considerable time during which the apparatus is unable to start the image forming operation.